Human traces in urban places.

Over the last two centuries many major cities have undergone large-scale modernisation that has led to the growing sense of homogenisation associated with such locales across the globe. The fractal logic that is at the heart of so many urban settings, where the whole system is made up of parts that are identical to the whole, seems to serve in making anonymous everyday experiences. Public transport and its corresponding street furniture, if thoughtfully designed and planned, has the potential to form an integral element in the promotion of a sense of identity, interconnectedness and flow within a city. Furthermore, bus stops, benches, litter bins, curb-sides, posts and pavements, to mention a few, offer interesting cases to consider how people truly engage with contemporary urban spaces. These objects—part of routine and made familiar—are elements of daily lives that are ingredients towards visual and multi-modal experiences. In addition, these are places where individuals encounter sociality and materiality in ordinary and sometimes extraordinary ways. This paper uses a visual ethnographic approach towards exploring the human traces of routine activities that have an impact on the cityscape. An Investigation of these details found within the urban landscape lead us towards understanding how we engage with and navigate cities. This is essentially an urban archaeological study that looks to reveal how non-designed phenomenon in urban places can contribute to our image of a city, providing a reflection on homogeneity within the built environment. Our visual ethnography focuses on six major cities: two each in Britain, Europe and North America. The findings of this work illustrate through visual analyses three key characteristics: first, how urban spaces are transformed intentionally and unintentionally; second, how transformations are practical, functional, beautiful and sometimes ridiculous; third, how transformations reveal values around visual and multi-modal experiences inherent to people.

When is bigger better? The effects of group size on the evolution of helping behaviours.

Understanding the evolution of sociality in humans and other species requires understanding how selection on social behaviour varies with group size. However, the effects of group size are frequently obscured in the theoretical literature, which often makes assumptions that are at odds with empirical findings. In particular, mechanisms are suggested as supporting large-scale cooperation when they would in fact rapidly become ineffective with increasing group size. Here we review the literature on the evolution of helping behaviours (cooperation and altruism), and frame it using a simple synthetic model that allows us to delineate how the three main components of the selection pressure on helping must vary with increasing group size. The first component is the marginal benefit of helping to group members, which determines both direct fitness benefits to the actor and indirect fitness benefits to recipients. While this is often assumed to be independent of group size, marginal benefits are in practice likely to be maximal at intermediate group sizes for many types of collective action problems, and will eventually become very small in large groups due to the law of decreasing returns. The second component is the response of social partners on the past play of an actor, which underlies conditional behaviour under repeated social interactions. We argue that under realistic conditions on the transmission of information in a population, this response on past play decreases rapidly with increasing group size so that reciprocity alone (whether direct, indirect, or generalised) cannot sustain cooperation in very large groups. The final component is the relatedness between actor and recipient, which, according to the rules of inheritance, again decreases rapidly with increasing group size. These results explain why helping behaviours in very large social groups are limited to cases where the number of reproducing individuals is small, as in social insects, or where there are social institutions that can promote (possibly through sanctioning) large-scale cooperation, as in human societies. Finally, we discuss how individually devised institutions can foster the transition from small-scale to large-scale cooperative groups in human evolution.